Custom rewrite rules for feeds of custom queries (query_var query strings in URL)?

Question

Question updated.

What I'm trying to do

If I want to display posts (or a feed of posts) that belong to a category AND a custom taxonomy, or a category AND a tag, or a custom taxonomy AND a tag, I can do so using query variables as query strings in URL.

But I want to prettify the URLs first, like so:

• example.com/?category_name=main&channel=tech to example.com/main/channel/tech/

• example.com/?category_name=main&channel=tech&feed=rss2 to example.com/main/channel/tech/feed/

• example.com/?category_name=main&tag=jsyk to example.com/main/tag/jsyk/

• example.com/?category_name=main&tag=jsyk&feed=rss2 to example.com/main/tag/jsyk/feed/

Where category_name defines the category slug, channel the custom taxonomy "Channel" term's slug, and tag the tag slug.

How I'm doing it

First, I tried reading as many examples as possible, including:

• http://codex.wordpress.org/Class_Reference/WP_Rewrite

• Need help with add_rewrite_rule

• Need help with friendly URL's in Wordpress

• Custom rewrite rules for a $_GET request

• custom post type and custom taxonomy permalink

• Taxonomy based permalinks

I place all theme independent functions for my site in a must-use plugin, which looks like this:

<?php
/*
 * Plugin Name: Default Functions
 * Description: Site-specific functions for example.com
 */

/* Add functions below */



/* THE END */

That's where I added my rewrite function which looks like this:

function wtnerd_edition_specific_categories( $wp_rewrite ) {
    $rewrite_rules = array(
        '([a-zA-Z0-9-_^/]+)/channel/([a-zA-Z0-9-_^/]+)' => 'index.php?category_name='.$wp_rewrite->preg_index(1).'&channel='.$wp_rewrite->preg_index(2),

        '([a-zA-Z0-9-_^/]+)/channel/([a-zA-Z0-9-_^/]+)/feed' => 'index.php?category_name='.$wp_rewrite->preg_index(1).'&channel='.$wp_rewrite->preg_index(2).'&feed=rss2',

        '([a-zA-Z0-9-_^/]+)/section/([a-zA-Z0-9-_^/]+)' => 'index.php?category_name='.$wp_rewrite->preg_index(1).'&tag='.$wp_rewrite->preg_index(2),

        '([a-zA-Z0-9-_^/]+)/section/([a-zA-Z0-9-_^/]+)/feed' => 'index.php?category_name='.$wp_rewrite->preg_index(1).'&tag='.$wp_rewrite->preg_index(2).'&feed=rss2'
    );
    $wp_rewrite->rules = $rewrite_rules + $wp_rewrite->rules;
}
add_filter( 'generate_rewrite_rules', 'wtnerd_edition_specific_categories' );

Problem

The feed URLs don't work. For example:

example.com/main/channel/tech/feed/

loads the content-none.php template instead of showing the actual feed of posts that belong to the said terms.

I am not sure how to fix this.

Answer 1

You can use add_rewrite_rule hooked to the init action, instead of using the generate_rewrite_rules filter (where it gets a bit low-level).

But the actual problem with your rewrite rules is the regex in place. Here's what it'd look like:

function wtnerd_edition_specific_categories() {
    add_rewrite_rule( '(.+?)/channel/(.+?)/feed/(feed|rdf|rss|rss2|atom)/?$', 'index.php?category_name=$matches[1]&channel=$matches[2]&feed=$matches[3]', 'top' );
    add_rewrite_rule( '(.+?)/channel/(.+?)/(feed|rdf|rss|rss2|atom)/?$', 'index.php?category_name=$matches[1]&channel=$matches[2]&feed=$matches[3]', 'top' );
    add_rewrite_rule( '(.+?)/channel/(.+?)/page/?([0-9]{1,})/?$', 'index.php?category_name=$matches[1]&channel=$matches[2]&paged=$matches[3]', 'top' );
    add_rewrite_rule( '(.+?)/channel/(.+?)/?$', 'index.php?category_name=$matches[1]&channel=$matches[2]', 'top' );

    add_rewrite_rule( '(.+?)/section/(.+?)/feed/(feed|rdf|rss|rss2|atom)/?$', 'index.php?category_name=$matches[1]&tag=$matches[2]&feed=$matches[3]', 'top' );
    add_rewrite_rule( '(.+?)/section/(.+?)/(feed|rdf|rss|rss2|atom)/?$', 'index.php?category_name=$matches[1]&tag=$matches[2]&feed=$matches[3]', 'top' );
    add_rewrite_rule( '(.+?)/section/(.+?)/page/?([0-9]{1,})/?$', 'index.php?category_name=$matches[1]&tag=$matches[2]&paged=$matches[3]', 'top' );
    add_rewrite_rule( '(.+?)/section/(.+?)/?$', 'index.php?category_name=$matches[1]&tag=$matches[2]', 'top' );
}
add_action( 'init', 'wtnerd_edition_specific_categories' );

You can also use rewrite_rules_array filter hook.